/*
 * JFugue - API for Music Programming
 * Copyright (C) 2003-2008  David Koelle
 *
 * http://www.jfugue.org 
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *  
 */

package org.jfugue;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.sound.midi.MidiEvent;
import javax.sound.midi.Sequence;
import javax.sound.midi.Track;

/**
 * Takes the events in a MIDI sequence and places them into a time-based map.
 * This is done so the events can be played back in order of when the events
 * occur, regardless of the tracks they happen to be in. This is useful when
 * sending events to an external device, or any occasion when iterating through
 * the tracks is not useful because the tracks would be played sequentially
 * rather than in parallel.
 * 
 * @author David Koelle
 * @version 3.0
 */
public final class TimeEventManager {
	public static final long sortSequenceByTimestamp(Sequence sequence,
			Map<Long, List<MidiEvent>> timeMap) {
		// Keep track of how long the sequence is
		long longestTime = 0;

		// Iterate through the tracks, and store the events into our time map
		Track[] tracks = sequence.getTracks();
		for (int i = 0; i < tracks.length; i++) {
			for (int e = 0; e < tracks[i].size(); e++) {
				// Get MIDI message and time data from event
				MidiEvent event = tracks[i].get(e);
				long timestamp = event.getTick();

				// Put the MIDI message into the time map
				List<MidiEvent> list = null;
				if ((list = timeMap
						.get(timestamp)) == null) {
					// Add a new list to the map if one doesn't already exist
					// for the timestamp in question
					list = new ArrayList<MidiEvent>();
					timeMap.put(timestamp, list);
				}
				list.add(event);

				// Update the longest time known, if required
				if (timestamp > longestTime) {
					longestTime = timestamp;
				}
			}
		}

		return longestTime;
	}

	/**
	 * Returns the events from this sequence in temporal order. This is done in
	 * a two step process: 1. mapSequence() populates timeMap. Each timestamp
	 * key in timeMap is mapped to a List of events that take place at that time
	 * 2. A list of all events from all timestamps is created and returned
	 * 
	 * @return The events from the sequence, in temporal order
	 */
	public static final List<MidiEvent> getAllEventsSortedByTimestamp(
			Sequence sequence) {
		Map<Long, List<MidiEvent>> timeMap = new HashMap<Long, List<MidiEvent>>();
		long longestTime = sortSequenceByTimestamp(sequence, timeMap);

		List<MidiEvent> totalList = new ArrayList<MidiEvent>();

		for (long l = 0; l < longestTime; l++) {
			Long key = new Long(l);
			if (timeMap.containsKey(key)) {
				List<MidiEvent> list = timeMap.get(key);
				totalList.addAll(list);
			}
		}

		return totalList;
	}
}
